Contents at a Glance
People have come up with many interesting ideas to help save the Earth from an asteroid impact like moving asteroids with lasers, Sun’s rays & thermal electrostatic pushing!
Some time will be spent during the NEOShield project to filter through some of the more exotic of these ideas to see if there are any that could be applied to a real mission, capable of moving an asteroid from its initial course.
The purpose of investigating the more exotic alternative methods of moving an asteroid is to ensure the NEOShield project is comprehensive. It is not intended to dismiss any ideas out of hand, but instead to ensure that only the best methods for asteroid deflection are carried forward into the future.
Here are some that have been considered.
Moving asteroids with lasers
There are two broad ideas discussed in papers related to moving asteroids with lasers.
Lasers could be used to heat the asteroid and make its surface boiling. The gas released could act as a thruster to change the asteroid orbit.
The light itself exert a small force, a large enough laser could potentially do the same moving small asteroid.
Focusing the Sun’s energy
The use of large mirrors or lenses to concentrate the Sun’s energy onto an asteroid using single or multiple spacecraft is an idea that has been discussed in numerous publications.
The sunlight would have the same effect as laser light: material boiled of from the surface pushes the asteroids away, along with the photons contribution that would give a little push.
Changing an asteroid’s thermal properties
The orbit of an asteroid is affected by its thermal properties so it stands to reason that changing the overall thermal properties of an asteroid should result in a change of its orbit.
Many ideas have been suggested as to how this can be achieved: from painting an asteroid white, to shading it from the Sun.
Electrostatic methods are often described as having much greater potential than gravity-based methods of asteroid deflection since the electrostatic force is so much stronger than gravity.
It would be in principle possible to explore the effectiveness of using electrostatics to push an asteroid off course.